The Center for Clinical Epidemiology and Biostatistics (CCEB), the Renal-Electrolyte and Hypertension Division of the Department of Medicine, and the Division of Nephrology of the Department of Pediatrics, all of the University of Pennsylvania (Penn) School of Medicine, submit this application to continue and expand an innovative and successful post-doctoral training program for clinicians and scientists in nephrology clinical research. Penn promotes an academic environment in which basic and clinical research are encouraged and viewed as attractive career paths. This training program attracts nephrology trainees from institutions nationwide; its graduate programs are placed in institutions nationwide, resulting in a program of high impact. The two- to three-year training program consists of required courses in clinical epidemiology, research methodology, biostatistics, and renal epidemiology; elective courses relevant to the trainees' methodologic interests; journal clubs and clinical research conferences focusing on research issues in nephrology; extensive independent readings; participation in research seminars at the CCEB and adult and pediatric nephrology divisions; and the completion of a mentored independent research project in renal epidemiology. Two training pathways are included. Pathway One is for nephrologists without formal research training. Pathway Two is for PhD-trained scientists who desire advanced epidemiology training focusing on applying epidemiologic methods to kidney disease. The program: 1) trains scientists to be rigorous and independent academic investigators able to use a broad array of epidemiological methods to address research issues in nephrology related to the etiology, prognosis, prevention, early detection, treatment, clinical economics, technology assessment, medical decision making, and quality of patient care; 2) provides a closely mentored research experience with faculty preceptors in clinical epidemiology and nephrology; and 3) strengthens the links between traditional epidemiology and nephrology. With the expansion of this program, three fellowship slots will be awarded each year. Most trainees will matriculate in the Master of Science in Clinical Epidemiology (MSCE) degree program. Strengths of the proposed program are: 1) the long history of successful research training programs in the CCEB and adult and pediatric divisions of nephrology; 2) the collaborative links that already have been forged among the three programs; 3) the comprehensive course offerings and ongoing research programs available to trainees; and 4) the successful training records of the program directors and faculty. In addition, the availability of the broad range of rich expertise of the faculties in the CCEB and the adult and pediatric nephrology divisions; numerous existing large databases that can be used for research projects and training; a broad array of specialized analytic capabilities available for clinical studies (e.g., clinical trials, case-control, cohort research, etc.); and the faculties' commitment to collaborative research and training combine to provide an ideal environment for this training program.